PHPStan: should be contravariant with parameter

[Hanmac]

Issue:
Methods defined in Parent with parent related type
are overwritten in Child with Child related type

Found solution, adding Template Params:
https://phpstan.org/r/b4926398-b0bf-400e-b053-e54c21d560bd

this may not be needed, depending on the function:

/**
  * @param AModel $model
  */

I will make extra issues/MRs for all the related ones.

List:

• Varien_Object: fix contravariant with implements ArrayAccess #5678

[Hanmac]

My thoughts on giving Mage_Core_Model_Resource_Abstract a template type for their Objects:

Mage_Core_Model_Resource_Abstract can't have Template type with Varien_Object
and Mage_Core_Model_Resource_Db_Abstract can't have Template type with Mage_Core_Model_Abstract

because there are some out liners, especially in Mage_Core that doesn't inherit from Mage_Core_Model_Abstract :/